Articles de revues : « Portable mobile mapping »

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Nüchter, A., D. Borrmann, P. Koch, M. Kühn et S. May. « A MAN-PORTABLE, IMU-FREE MOBILE MAPPING SYSTEM ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-3/W5 (19 août 2015) : 17–23. http://dx.doi.org/10.5194/isprsannals-ii-3-w5-17-2015.

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Mobile mapping systems are commonly mounted on cars, ships and robots. The data is directly geo-referenced using GPS data and expensive IMU (inertial measurement systems). Driven by the need for flexible, indoor mapping systems we present an inexpensive mobile mapping solution that can be mounted on a backpack. It combines a horizontally mounted 2D profiler with a constantly spinning 3D laser scanner. The initial system featuring a low-cost MEMS IMU was revealed and demonstrated at MoLaS: Technology Workshop Mobile Laser Scanning at Fraunhofer IPM in Freiburg in November 2014. In this paper, we present an IMU-free solution.

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Al-Hamad, A., et N. El-Sheimy. « Smartphones Based Mobile Mapping Systems ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-5 (5 juin 2014) : 29–34. http://dx.doi.org/10.5194/isprsarchives-xl-5-29-2014.

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The past 20 years have witnessed an explosive growth in the demand for geo-spatial data. This demand has numerous sources and takes many forms; however, the net effect is an ever-increasing thirst for data that is more accurate, has higher density, is produced more rapidly, and is acquired less expensively. For mapping and Geographic Information Systems (GIS) projects, this has been achieved through the major development of Mobile Mapping Systems (MMS). MMS integrate various navigation and remote sensing technologies which allow mapping from moving platforms (e.g. cars, airplanes, boats, etc.) to obtain the 3D coordinates of the points of interest. Such systems obtain accuracies that are suitable for all but the most demanding mapping and engineering applications. However, this accuracy doesn't come cheaply. As a consequence of the platform and navigation and mapping technologies used, even an "inexpensive" system costs well over 200 000 USD. Today's mobile phones are getting ever more sophisticated. Phone makers are determined to reduce the gap between computers and mobile phones. Smartphones, in addition to becoming status symbols, are increasingly being equipped with extended Global Positioning System (GPS) capabilities, Micro Electro Mechanical System (MEMS) inertial sensors, extremely powerful computing power and very high resolution cameras. Using all of these components, smartphones have the potential to replace the traditional land MMS and portable GPS/GIS equipment. This paper introduces an innovative application of smartphones as a very low cost portable MMS for mapping and GIS applications.

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Torresani, Alessandro, Fabio Menna, Roberto Battisti et Fabio Remondino. « A V-SLAM Guided and Portable System for Photogrammetric Applications ». Remote Sensing 13, n^o 12 (16 juin 2021) : 2351. http://dx.doi.org/10.3390/rs13122351.

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Mobile and handheld mapping systems are becoming widely used nowadays as fast and cost-effective data acquisition systems for 3D reconstruction purposes. While most of the research and commercial systems are based on active sensors, solutions employing only cameras and photogrammetry are attracting more and more interest due to their significantly minor costs, size and power consumption. In this work we propose an ARM-based, low-cost and lightweight stereo vision mobile mapping system based on a Visual Simultaneous Localization And Mapping (V-SLAM) algorithm. The prototype system, named GuPho (Guided Photogrammetric System), also integrates an in-house guidance system which enables optimized image acquisitions, robust management of the cameras and feedback on positioning and acquisition speed. The presented results show the effectiveness of the developed prototype in mapping large scenarios, enabling motion blur prevention, robust camera exposure control and achieving accurate 3D results.

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Cullen, C., G. MacKenzie, A. A. J. Adgey, J. McC Anderson, G. J. Dempsey, G. T. H. Wright, M. Crawley, E. T. McAdams et J. McLaughlin. « Portable Cardiac Mapping Assessment of Acute Ischaemic Injury ». Methods of Information in Medicine 33, n^o 01 (1994) : 72–75. http://dx.doi.org/10.1055/s-0038-1634985.

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Abstract:A portable cardiac mapping system is used to improve the accuracy of diagnosis of acute ischaemic injury outside hospital. Patients presenting chest pain suggestive of myocardial infarction (Ml) were mapped by attendant medical personnel operating from a mobile coronary unit. These first Ml maps were compared against average normal maps using QRS and ST-T isointegral values. Discriminant function analysis performed on the parameters achieved a sensitivity of 90% and a specificity of 96%.

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Maset, E., S. Cucchiaro, F. Cazorzi, F. Crosilla, A. Fusiello et A. Beinat. « INVESTIGATING THE PERFORMANCE OF A HANDHELD MOBILE MAPPING SYSTEM IN DIFFERENT OUTDOOR SCENARIOS ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2021 (28 juin 2021) : 103–9. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2021-103-2021.

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Abstract. In recent years, portable Mobile Mapping Systems (MMSs) are emerging as valuable survey instruments for fast and efficient mapping of both internal and external environments. The aim of this work is to assess the performance of a commercial handheld MMS, Gexcel HERON Lite, in two different outdoor applications. The first is the mapping of a large building, which represents a standard use-case scenario of this technology. Through the second case study, that consists in the survey of a torrent reach, we investigate instead the applicability of the handheld MMS for natural environment monitoring, a field in which portable systems are not yet widely employed. Quantitative and qualitative assessment is presented, comparing the point clouds obtained from the HERON Lite system against reference models provided by traditional techniques (i.e., Terrestrial Laser Scanning and Photogrammetry).

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Yu, Peidong, Mengke Wang et Huanjian Chen. « Integration and evaluation of SLAM-based backpack mobile mapping system ». E3S Web of Conferences 206 (2020) : 03014. http://dx.doi.org/10.1051/e3sconf/202020603014.

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Mobile mapping is an efficient technology to acquire spatial data of the environment. As a supplement of vehicle-borne and air-borne methods, Backpack mobile mapping system (MMS) has a wide application prospect in indoor and underground space. High-precision positioning and attitude determination are the key to MMS. Usually, GNSS/INS integrated navigation system provides reliable pose information. However, in the GNSS-denied environments, there is no effective long-term positioning method. With the development of simultaneous localization and mapping (SLAM) algorithm, it provides a new solution for indoor mobile mapping. This paper develops a portable backpack mobile mapping system, which integrates multi-sensor such as LiDAR, IMU, GNSS and panoramic camera. The 3D laser SLAM algorithm is applied to the mobile mapping to realize the acquisition of geographic information data in various complex environments. The experimental results in typical indoor and outdoor scenes show that the system can achieve high-precision and efficient acquisition of 3D information, and the relative precision of point cloud is 2~4cm, which meets the requirements of scene mapping and reconstruction.

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Rashidan, M. H., I. A. Musliman et A. A. Rahman. « GEOPACKAGE DATA FORMAT FOR COLLABORATIVEMAPPING OF GEOSPATIAL DATAIN LIMITED NETWORKENVIRONMENTS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W1 (29 septembre 2016) : 15–21. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w1-15-2016.

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With the growth of technology in earth and space science informatics has led to the revolution in a wide range of geospatial practice. Nowadays collaborative mapping has become a new hot spot, following mobile and web GIS. This paper explores the potential use of GeoPackage for collaborative mapping of geospatial data in limited network environments. GeoPackage is a data format that open-standard, platform-independent, portable, and self-describing. This paper focus on the implementation of GeoPackage in mobile application for field data collection. A mobile application was developed that implements the GeoPackage data format as an internal database to provide support for offline mapping. The developed mobile application demonstrates that vector and raster data can be stored in a single data format, which reduces the device storage consumption. The details of how GeoPackage data contribute to mobile GIS to achieve collaborative mapping in limited network environments are discussed. The findings show that the GeoPackage data format has great potential to improve existing mobile GIS applications.

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Lin, Yi-Chun, Raja Manish, Darcy Bullock et Ayman Habib. « Comparative Analysis of Different Mobile LiDAR Mapping Systems for Ditch Line Characterization ». Remote Sensing 13, n^o 13 (25 juin 2021) : 2485. http://dx.doi.org/10.3390/rs13132485.

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Maintenance of roadside ditches is important to avoid localized flooding and premature failure of pavements. Scheduling effective preventative maintenance requires a reasonably detailed mapping of the ditch profile to identify areas in need of excavation to remove long-term sediment accumulation. This study utilizes high-resolution, high-quality point clouds collected by mobile LiDAR mapping systems (MLMS) for mapping roadside ditches and performing hydrological analyses. The performance of alternative MLMS units, including an unmanned aerial vehicle, an unmanned ground vehicle, a portable backpack system along with its vehicle-mounted version, a medium-grade wheel-based system, and a high-grade wheel-based system, is evaluated. Point clouds from all the MLMS units are in agreement within the ±3 cm range for solid surfaces and ±7 cm range for vegetated areas along the vertical direction. The portable backpack system that could be carried by a surveyor or mounted on a vehicle is found to be the most cost-effective method for mapping roadside ditches, followed by the medium-grade wheel-based system. Furthermore, a framework for ditch line characterization is proposed and tested using datasets acquired by the medium-grade wheel-based and vehicle-mounted portable systems over a state highway. An existing ground-filtering approach—cloth simulation—is modified to handle variations in point density of mobile LiDAR data. Hydrological analyses, including flow direction and flow accumulation, are applied to extract the drainage network from the digital terrain model (DTM). Cross-sectional/longitudinal profiles of the ditch are automatically extracted from the LiDAR data and visualized in 3D point clouds and 2D images. The slope derived from the LiDAR data turned out to be very close to the highway cross slope design standards of 2% on driving lanes, 4% on shoulders, and a 6-by-1 slope for ditch lines.

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Brogan, Michael, Simon McLoughlin et Catherine Deegan. « Assessment of stereo camera calibration techniques for a portable mobile mapping system ». IET Computer Vision 7, n^o 3 (juin 2013) : 209–17. http://dx.doi.org/10.1049/iet-cvi.2012.0085.

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Kohira, K., et H. Masuda. « POINT-CLOUD COMPRESSION FOR VEHICLE-BASED MOBILE MAPPING SYSTEMS USING PORTABLE NETWORK GRAPHICS ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W4 (13 septembre 2017) : 99–106. http://dx.doi.org/10.5194/isprs-annals-iv-2-w4-99-2017.

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A mobile mapping system is effective for capturing dense point-clouds of roads and roadside objects．Point-clouds of urban areas, residential areas, and arterial roads are useful for maintenance of infrastructure, map creation, and automatic driving. However, the data size of point-clouds measured in large areas is enormously large. A large storage capacity is required to store such point-clouds, and heavy loads will be taken on network if point-clouds are transferred through the network. Therefore, it is desirable to reduce data sizes of point-clouds without deterioration of quality. In this research, we propose a novel point-cloud compression method for vehicle-based mobile mapping systems. In our compression method, point-clouds are mapped onto 2D pixels using GPS time and the parameters of the laser scanner. Then, the images are encoded in the Portable Networking Graphics (PNG) format and compressed using the PNG algorithm. In our experiments, our method could efficiently compress point-clouds without deteriorating the quality.

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Lovas, T., K. Hadzijanisz, V. Papp et A. J. Somogyi. « INDOOR BUILDING SURVEY ASSESSMENT ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2020 (6 août 2020) : 251–57. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2020-251-2020.

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Abstract. There are multiple emerging technologies, devices and integrated equipment to support indoor mapping. The two main categories are the wearable/portable (e.g. hand-held or backpack devices) and the trolley based devices. The most widely used sensors of the integrated systems are the laser scanners (usually profile scanners), camera(s) and the IMU unit. Compared to outdoor mobile mapping systems the main difference is the lack of GNSS signals; localization is usually supported by SLAM (Simultaneous Localization and Mapping) technology, using Kalman-filtering. Current paper discusses the assessment of the potential of trolley-based indoor mobile mapping systems (MMS) by surveying a building part by multiple technologies. Besides conventional land surveying measurements, terrestrial lasers scanning and a backpack-based mobile survey have been carried out. The analysis included cloud-to-cloud comparison as well as CAD-based evaluation focusing on the geometric accuracy of the point clouds. The paper also presents the surveying workflow; on its resource-needs and potential application fields. The paper discusses the data acquisition technologies and procedures and the different quality assessment methods and results. Since an experimental survey was conducted with a backpack-based unit in the same study area, the paper gives a brief overview on how the two different mobile mapping technologies can be applied indoor, and presents the main differences, advantages and drawbacks.

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Maset, E., R. Valente, M. Iamoni, M. Haider et A. Fusiello. « INTEGRATION OF PHOTOGRAMMETRY AND PORTABLE MOBILE MAPPING TECHNOLOGY FOR 3D MODELING OF CULTURAL HERITAGE SITES : THE CASE STUDY OF THE BZIZA TEMPLE ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2022 (30 mai 2022) : 831–37. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2022-831-2022.

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Abstract. In this paper, we present a multi-sensor approach employed to obtain the 3D model of the Roman temple of Bziza (Lebanon) and its surroundings, a work carried out as part of the archaeological Northern Lebanon Project (NoLeP). The integration of photogrammetry and portable mobile mapping technology was tested to overcome the weaknesses of each individual surveying method, with the aim of producing a complete and realistic 3D reconstruction of the whole site, as well as capturing at high-resolution the architectural features of the main structure. Moreover, this case study serves to further investigate the accuracy that can be reached with mobile laser scanners, highlighting benefits and limitations of this rapid and efficient mapping technique also in the field of Cultural Heritage documentation.

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Venkatraman Jagatha, Janani, André Klausnitzer, Miriam Chacón-Mateos, Bernd Laquai, Evert Nieuwkoop, Peter van der Mark, Ulrich Vogt et Christoph Schneider. « Calibration Method for Particulate Matter Low-Cost Sensors Used in Ambient Air Quality Monitoring and Research ». Sensors 21, n^o 12 (8 juin 2021) : 3960. http://dx.doi.org/10.3390/s21123960.

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Over the last decade, manufacturers have come forth with cost-effective sensors for measuring ambient and indoor particulate matter concentration. What these sensors make up for in cost efficiency, they lack in reliability of the measured data due to their sensitivities to temperature and relative humidity. These weaknesses are especially evident when it comes to portable or mobile measurement setups. In recent years many studies have been conducted to assess the possibilities and limitations of these sensors, however mostly restricted to stationary measurements. This study reviews the published literature until 2020 on cost-effective sensors, summarizes the recommendations of experts in the field based on their experiences, and outlines the quantile-mapping methodology to calibrate low-cost sensors in mobile applications. Compared to the commonly used linear regression method, quantile mapping retains the spatial characteristics of the measurements, although a common correction factor cannot be determined. We conclude that quantile mapping can be a useful calibration methodology for mobile measurements given a well-elaborated measurement plan assures providing the necessary data.

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Li-Chee-Ming, Julien, et Costas Armenakis. « Introduction to a Portable Stereo Mapping System for Unmanned Vehicles ». GEOMATICA 66, n^o 4 (décembre 2012) : 323–32. http://dx.doi.org/10.5623/cig2012-057.

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This work introduces a Mobile Stereo Mapping System (MSMS) designed for remote operation onboard unmanned vehicles for navigation and rapid collection of 3D spatial data through direct georeferencing and integration of optical and multiple navigation sensors. By avoiding the need for ground control points, the system offers a low-cost mapping solution for both kinematic and static cases, rapid deployments, high data resolutions, and low risk to operators. Position estimation of the camera is based on differential GPS, loosely coupled in a Kalman filter with a low-cost Micro Electro-Mechanical Systems (MEMS) based Inertial Measurement Unit (IMU). Attitude is estimated from gyroscope data, aided by accelerometer and magnetometer data to compensate for gyro drift. Two low-cost consumer digital cameras are calibrated and time-synchronized with the GPS/IMU to provide directly georeferenced stereo imagery. The MSMS determines mapping coordinates using photogrammetric solutions modified for direct georeferencing. A calibration process has been developed for the sensor components and the integrated system itself to determine systematic errors and biases, and to determine the relative geometry of the sensors. Object space accuracies (Root Mean Square Error (RMSE)) in the range of 1/100 at camera-to-object distances of about 30m were achieved using wide baseline overlapping images taken from two separate positions of the stereo-metric MSMS. The system design and the calibration and mapping accuracy of the MSMS are presented and assessed using field testing.

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Blaser, S., S. Cavegn et S. Nebiker. « DEVELOPMENT OF A PORTABLE HIGH PERFORMANCE MOBILE MAPPING SYSTEM USING THE ROBOT OPERATING SYSTEM ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-1 (26 septembre 2018) : 13–20. http://dx.doi.org/10.5194/isprs-annals-iv-1-13-2018.

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Abstract. The rapid progression in digitalization in the construction industry and in facility management creates an enormous demand for the efficient and accurate reality capturing of indoor spaces. Cloud-based services based on georeferenced metric 3D imagery are already extensively used for infrastructure management in outdoor environments. The goal of our research is to enable such services for indoor applications as well. For this purpose, we designed a portable mobile mapping research platform with a strong focus on acquiring accurate 3D imagery. Our system consists of a multi-head panorama camera in combination with two multi-profile LiDAR scanners and a MEMS-based industrial grade IMU for LiDAR-based online and offline SLAM. Our modular implementation based on the Robot Operating System enables rapid adaptations of the sensor configuration and the acquisition software. The developed workflow provides for completely GNSS-independent data acquisition and camera pose estimation using LiDAR-based SLAM. Furthermore, we apply a novel image-based georeferencing approach for further improving camera poses. First performance evaluations show an improvement from LiDAR-based SLAM to image-based georeferencing by an order of magnitude: from 10&ndash;13cm to 1.3&ndash;1.8cm in absolute 3D point accuracy and from 8&ndash;12cm to sub-centimeter in relative 3D point accuracy.

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Blaser, S., S. Nebiker et D. Wisler. « PORTABLE IMAGE-BASED HIGH PERFORMANCE MOBILE MAPPING SYSTEM IN UNDERGROUND ENVIRONMENTS – SYSTEM CONFIGURATION AND PERFORMANCE EVALUATION ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W5 (29 mai 2019) : 255–62. http://dx.doi.org/10.5194/isprs-annals-iv-2-w5-255-2019.

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Abstract. The progression in urbanization increases the need for different types of underground infrastructure. Consequently, infrastructure and life cycle management are rapidly gaining in importance. Mobile reality capturing systems and cloud-based services exploiting georeferenced metric 3D imagery are already extensively used for infrastructure management in outdoor environments. These services minimise dangerous and expensive field visits or measurement campaigns. In this paper, we introduce the BIMAGE Backpack, a portable image-based mobile mapping system for 3D data acquisition in indoor environments. The system consists of a multi-head panorama camera, two multi-profile laser scanners and an inertial measurement unit. With this system, we carried out underground measurement campaigns in the Hagerbach Test Gallery, located in Flums Hochwiese, Switzerland. For our performance evaluations in two different tunnel sections, we employed LiDAR SLAM as well as advanced image-based georeferencing. The obtained absolute accuracies were in the range from 6.2 to 7.4&thinsp;cm. The relative accuracy, which for many applications is even more important, was in the range of 2&ndash;6&thinsp;mm. These figures demonstrate an accuracy improvement of the subsequent image-based georeferencing over LiDAR SLAM by about an order of magnitude. The investigations show the application potential of image-based portable mobile mapping systems for infrastructure inventory and management in large underground facilities.

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Rodríguez-Martín, Rodríguez-Gonzálvez, Ruiz de Oña Crespo et González-Aguilera. « Validation of Portable Mobile Mapping System for Inspection Tasks in Thermal and Fluid–Mechanical Facilities ». Remote Sensing 11, n^o 19 (20 septembre 2019) : 2205. http://dx.doi.org/10.3390/rs11192205.

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The three-dimensional registration of industrial facilities has a great importance for maintenance, inspection, and safety tasks and it is a starting point for new improvements and expansions in the industrial facilities context. In this paper, a comparison between the results obtained using a novel portable mobile mapping system (PMMS) and a static terrestrial laser scanner (TLS), widely used for 3D reconstruction in civil and industrial scenarios, is carried out. This comparison is performed in the context of industrial inspection tasks, specifically in the thermal and fluid-mechanics facilities in a hospital. The comparison addresses the general reconstruction of a machine room, focusing on the quantitative and qualitative analysis of different elements (e.g., valves, regulation systems, burner systems and tanks, etc.). The validation of the PMMS is provided considering the TLS as ground truth and applying a robust statistical analysis. Results come to confirm the suitability of the PMMS to perform inspection tasks in industrial facilities.

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* et *. « A Self-Assembly Portable Mobile Mapping System for Archeological Reconstruction Based on VSLAM-Photogrammetric Algorithm ». Sensors 19, n^o 18 (12 septembre 2019) : 3952. http://dx.doi.org/10.3390/s19183952.

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Three Dimensional (3D) models are widely used in clinical applications, geosciences, cultural heritage preservation, and engineering; this, together with new emerging needs such as building information modeling (BIM) develop new data capture techniques and devices with a low cost and reduced learning curve that allow for non-specialized users to employ it. This paper presents a simple, self-assembly device for 3D point clouds data capture with an estimated base price under €2500; furthermore, a workflow for the calculations is described that includes a Visual SLAM-photogrammetric threaded algorithm that has been implemented in C++. Another purpose of this work is to validate the proposed system in BIM working environments. To achieve it, in outdoor tests, several 3D point clouds were obtained and the coordinates of 40 points were obtained by means of this device, with data capture distances ranging between 5 to 20 m. Subsequently, those were compared to the coordinates of the same targets measured by a total station. The Euclidean average distance errors and root mean square errors (RMSEs) ranging between 12–46 mm and 8–33 mm respectively, depending on the data capture distance (5–20 m). Furthermore, the proposed system was compared with a commonly used photogrammetric methodology based on Agisoft Metashape software. The results obtained demonstrate that the proposed system satisfies (in each case) the tolerances of ‘level 1’ (51 mm) and ‘level 2’ (13 mm) for point cloud acquisition in urban design and historic documentation, according to the BIM Guide for 3D Imaging (U.S. General Services).

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Tsai, G. J., Y. L. Chen, K. W. Chiang et Y. C. Lai. « THE GENERATION OF BUILDING FLOOR PLANS USING PORTABLE AND UNMANNED AERIAL VEHICLE MAPPING SYSTEMS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B4 (13 juin 2016) : 331–37. http://dx.doi.org/10.5194/isprs-archives-xli-b4-331-2016.

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Indoor navigation or positioning systems have been widely developed for Location-Based Services (LBS) applications and they come along with a keen demand of indoor floor plans for displaying results even improving the positioning performance. Generally, the floor plans produced by robot mapping focus on perceiving the environment to avoid obstacles and using the feature landmarks to update the robot position in the relative coordinate frame. These maps are not accurate enough to incorporate to the indoor positioning system. This study aims at developing Indoor Mobile Mapping System (Indoor MMS) and concentrates on generating the highly accurate floor plans based on the robot mapping technique using the portable, robot and Unmanned Aerial Vehicles (UAV) platform. The proposed portable mapping system prototype can be used in the chest package and the handheld approach. In order to evaluate and correct the generated floor plans from robot mapping techniques, this study builds the testing and calibration field using the outdoor control survey method implemented in the indoor environments. Based on control points and check points from control survey, this study presents the map rectification method that uses the affine transformation to solve the scale and deformation problems and also transfer the local coordinate system into world standard coordinate system. The preliminary results illustrate that the final version of the building floor plan reach 1 meter absolute positioning accuracy using the proposed mapping systems that combines with the novel map rectification approach proposed. These maps are well geo-referenced with world coordinate system thus it can be applied for future seamless navigation applications including indoor and outdoor scenarios.

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Tsai, G. J., Y. L. Chen, K. W. Chiang et Y. C. Lai. « THE GENERATION OF BUILDING FLOOR PLANS USING PORTABLE AND UNMANNED AERIAL VEHICLE MAPPING SYSTEMS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B4 (13 juin 2016) : 331–37. http://dx.doi.org/10.5194/isprsarchives-xli-b4-331-2016.

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Indoor navigation or positioning systems have been widely developed for Location-Based Services (LBS) applications and they come along with a keen demand of indoor floor plans for displaying results even improving the positioning performance. Generally, the floor plans produced by robot mapping focus on perceiving the environment to avoid obstacles and using the feature landmarks to update the robot position in the relative coordinate frame. These maps are not accurate enough to incorporate to the indoor positioning system. This study aims at developing Indoor Mobile Mapping System (Indoor MMS) and concentrates on generating the highly accurate floor plans based on the robot mapping technique using the portable, robot and Unmanned Aerial Vehicles (UAV) platform. The proposed portable mapping system prototype can be used in the chest package and the handheld approach. In order to evaluate and correct the generated floor plans from robot mapping techniques, this study builds the testing and calibration field using the outdoor control survey method implemented in the indoor environments. Based on control points and check points from control survey, this study presents the map rectification method that uses the affine transformation to solve the scale and deformation problems and also transfer the local coordinate system into world standard coordinate system. The preliminary results illustrate that the final version of the building floor plan reach 1 meter absolute positioning accuracy using the proposed mapping systems that combines with the novel map rectification approach proposed. These maps are well geo-referenced with world coordinate system thus it can be applied for future seamless navigation applications including indoor and outdoor scenarios.

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Cavegn, S., S. Blaser, S. Nebiker et N. Haala. « ROBUST AND ACCURATE IMAGE-BASED GEOREFERENCING EXPLOITING RELATIVE ORIENTATION CONSTRAINTS ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2 (28 mai 2018) : 57–64. http://dx.doi.org/10.5194/isprs-annals-iv-2-57-2018.

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Urban environments with extended areas of poor GNSS coverage as well as indoor spaces that often rely on real-time SLAM algorithms for camera pose estimation require sophisticated georeferencing in order to fulfill our high requirements of a few centimeters for absolute 3D point measurement accuracies. Since we focus on image-based mobile mapping, we extended the structure-from-motion pipeline COLMAP with georeferencing capabilities by integrating exterior orientation parameters from direct sensor orientation or SLAM as well as ground control points into bundle adjustment. Furthermore, we exploit constraints for relative orientation parameters among all cameras in bundle adjustment, which leads to a significant robustness and accuracy increase especially by incorporating highly redundant multi-view image sequences. We evaluated our integrated georeferencing approach on two data sets, one captured outdoors by a vehicle-based multi-stereo mobile mapping system and the other captured indoors by a portable panoramic mobile mapping system. We obtained mean RMSE values for check point residuals between image-based georeferencing and tachymetry of 2&thinsp;cm in an indoor area, and 3&thinsp;cm in an urban environment where the measurement distances are a multiple compared to indoors. Moreover, in comparison to a solely image-based procedure, our integrated georeferencing approach showed a consistent accuracy increase by a factor of 2&ndash;3 at our outdoor test site. Due to pre-calibrated relative orientation parameters, images of all camera heads were oriented correctly in our challenging indoor environment. By performing self-calibration of relative orientation parameters among respective cameras of our vehicle-based mobile mapping system, remaining inaccuracies from suboptimal test field calibration were successfully compensated.

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Perfetti, L., et F. Fassi. « HANDHELD FISHEYE MULTICAMERA SYSTEM : SURVEYING MEANDERING ARCHITECTONIC SPACES IN OPEN-LOOP MODE – ACCURACY ASSESSMENT ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-2/W1-2022 (25 février 2022) : 435–42. http://dx.doi.org/10.5194/isprs-archives-xlvi-2-w1-2022-435-2022.

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Abstract. The task of digitalizing meandering complex spaces in 3D is a challenging one even with the most advanced instrumentation like lightweight terrestrial laser scanner or portable/wearable Mobile Mapping Systems (MMSs). The complexity and extension of architectonic spaces such as staircases, corridors and passages are such that the acquisition time using static devices becomes prohibitive and the accuracy using mobile devices gets affected by drift error leading to warped models or requiring abundant control measurements. This paper presents a photogrammetric portable fisheye multicamera solution for the 3D survey of complex areas that aims at being both handy and fast in the acquisition as well as more reliable ad accurate than common MMSs. The paper showcases a stress test conducted on five complex reconstruction trajectories selected from the meandering connection passages of Milan’s Cathedral. The tests are constructed as worst-case scenario to evaluate the accuracy and drift error amount of the proposed system in open-ended unconstrained paths. The results, though still suffering from moderate drift error, highlights the potential of the solution, especially in retaining the overall shape and orthogonality of the architectonic elements acquired.

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Rodriguez-Martin, Manuel, Pablo Rodriguez-Gonzalvez, Diego Gonzalez-Aguilera et Erica Nocerino. « Novel Approach for Three-Dimensional Integral Documentation of Machine Rooms in Hospitals Using Portable Mobile Mapping System ». IEEE Access 6 (2018) : 79200–79210. http://dx.doi.org/10.1109/access.2018.2884922.

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McCarthy, Nicholas, Hamish McGowan, Adrien Guyot et Andrew Dowdy. « Mobile X-Pol Radar : A New Tool for Investigating Pyroconvection and Associated Wildfire Meteorology ». Bulletin of the American Meteorological Society 99, n^o 6 (juin 2018) : 1177–95. http://dx.doi.org/10.1175/bams-d-16-0118.1.

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AbstractThe process of pyroconvection occurs when fire-released heat, moisture, and/or aerosols induce or augment convection in the atmosphere. Prediction of pyroconvection presents a set of complex problems for meteorologists and wildfire managers. In particular, the turbulent characteristics of a pyroconvective plume exert bidirectional feedback on fire behavior, often with resulting severe impacts on life and property. Here, we present the motivation, field strategy, and initial results from the Bushfire Convective Plume Experiment, which through the use of mobile radar aims to quantify the kinematics of pyroconvection and its role in fire behavior. The case studies presented include world-first observations from two wildfires and one prescribed burn using the University of Queensland’s portable, dual-polarized X-band Doppler radar (UQ-XPOL). The initial analyses of reflectivity, Doppler winds, polarimetric variables, and spectrum width data provide insights into these relatively unexplored datasets within the context of pyroconvection. Weather radar data are supported by mesonet observations, time-lapse photography, airborne multispectral imaging, and spot-fire mapping. The ability to combine ground-validated fire intensity and progression at an hourly scale with quantitative data documenting the evolution of the convective plume kinematics at the scale of hundreds of meters represents a new capability for advancing our understanding of wildfires. The results demonstrate the suitability of portable, dual-polarized X-band Doppler radar to investigate pyroconvection and associated plume dynamics.

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Alreshidi, Ahmad, B. Altamimi, Sultan et Mehmood. « Software Architecture for Mobile Cloud Computing Systems ». Future Internet 11, n^o 11 (13 novembre 2019) : 238. http://dx.doi.org/10.3390/fi11110238.

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Mobile cloud computing (MCC) has recently emerged as a state-of-the-art technology for mobile systems. MCC enables portable and context-aware computation via mobile devices by exploiting virtually unlimited hardware and software resources offered by cloud computing servers. Software architecture helps to abstract the complexities of system design, development, and evolution phases to implement MCC systems effectively and efficiently. This paper aims to identify, taxonomically classify, and systematically map the state of the art on architecting MCC-based software. We have used an evidence-based software engineering (EBSE) approach to conduct a systematic mapping study (SMS) based on 121 qualitatively selected research studies published from 2006 to 2019. The results of the SMS highlight that architectural solutions for MCC systems are mainly focused on supporting (i) software as a service for mobile computing, (ii) off-loading mobile device data to cloud-servers, (iii) internet of things, edge, and fog computing along with various aspects like (iv) security and privacy of mobile device data. The emerging research focuses on the existing and futuristic challenges that relate to MCC-based internet of things (IoTs), mobile-cloud edge systems, along with green and energy-efficient computing. The results of the SMS facilitate knowledge transfer that could benefit researchers and practitioners to understand the role of software architecture to develop the next generation of mobile-cloud systems to support internet-driven computing.

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Chen, Mingjian, Weichang Yuan, Chang Cao, Colby Buehler, Drew R. Gentner et Xuhui Lee. « Development and Performance Evaluation of a Low-Cost Portable PM2.5 Monitor for Mobile Deployment ». Sensors 22, n^o 7 (4 avril 2022) : 2767. http://dx.doi.org/10.3390/s22072767.

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The concentration of fine particulate matter (PM2.5) is known to vary spatially across a city landscape. Current networks of regulatory air quality monitoring are too sparse to capture these intra-city variations. In this study, we developed a low-cost (60 USD) portable PM2.5 monitor called Smart-P, for use on bicycles, with the goal of mapping street-level variations in PM2.5 concentration. The Smart-P is compact in size (85 × 85 × 42 mm) and light in weight (147 g). Data communication and geolocation are achieved with the cyclist’s smartphone with the help of a user-friendly app. Good agreement was observed between the Smart-P monitors and a regulatory-grade monitor (mean bias error: −3.0 to 1.5 μg m−3 for the four monitors tested) in ambient conditions with relative humidity ranging from 38 to 100%. Monitor performance decreased in humidity > 70% condition. The measurement precision, represented as coefficient of variation, was 6 to 9% in stationary mode and 6% in biking mode across the four tested monitors. Street tests in a city with low background PM2.5 concentrations (8 to 9 μg m−3) and in two cities with high background concentrations (41 to 74 μg m−3) showed that the Smart-P was capable of observing local emission hotspots and that its measurement was not sensitive to bicycle speed. The low-cost and user-friendly nature are two features that make the Smart-P a good choice for empowering citizen scientists to participate in local air quality monitoring.

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Chen, Chao, Llewellyn Tang, Craig Matthew Hancock et Penghe Zhang. « Development of low-cost mobile laser scanning for 3D construction indoor mapping by using inertial measurement unit, ultra-wide band and 2D laser scanner ». Engineering, Construction and Architectural Management 26, n^o 7 (19 août 2019) : 1367–86. http://dx.doi.org/10.1108/ecam-06-2018-0242.

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Purpose The purpose of this paper is to introduce the development of an innovative mobile laser scanning (MLS) method for 3D indoor mapping. The generally accepted and used procedure for this type of mapping is usually performed using static terrestrial laser scanning (TLS) which is high-cost and time-consuming. Compared with conventional TLS, the developed method proposes a new idea with advantages of low-cost, high mobility and time saving on the implementation of a 3D indoor mapping. Design/methodology/approach This method integrates a low-cost 2D laser scanner with two indoor positioning techniques – ultra-wide band (UWB) and an inertial measurement unit (IMU), to implement a 3D MLS for reality captures from an experimental indoor environment through developed programming algorithms. In addition, a reference experiment by using conventional TLS was also conducted under the same conditions for scan result comparison to validate the feasibility of the developed method. Findings The findings include: preset UWB system integrated with a low-cost IMU can provide a reliable positioning method for indoor environment; scan results from a portable 2D laser scanner integrated with a motion trajectory from the IMU/UWB positioning approach is able to generate a 3D point cloud based in an indoor environment; and the limitations on hardware, accuracy, automation and the positioning approach are also summarized in this study. Research limitations/implications As the main advantage of the developed method is low-cost, it may limit the automation of the method due to the consideration of the cost control. Robotic carriers and higher-performance 2D laser scanners can be applied to realize panoramic and higher-quality scan results for improvements of the method. Practical implications Moreover, during the practical application, the UWB system can be disturbed by variances of the indoor environment, which can affect the positioning accuracy in practice. More advanced algorithms are also needed to optimize the automatic data processing for reducing errors caused by manual operations. Originality/value The development of this MLS method provides a novel idea that integrates data from heterogeneous systems or sensors to realize a practical aim of indoor mapping, and meanwhile promote the current laser scanning technology to a lower-cost, more flexible, more portable and less time-consuming trend.

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Gutierrez, Evelyn, Benjamín Castañeda, Sylvie Treuillet et Ivan Hernandez. « Multimodal and Multiview Wound Monitoring with Mobile Devices ». Photonics 8, n^o 10 (2 octobre 2021) : 424. http://dx.doi.org/10.3390/photonics8100424.

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Along with geometric and color indicators, thermography is another valuable source of information for wound monitoring. The interaction of geometry with thermography can provide predictive indicators of wound evolution; however, existing processes are focused on the use of high-cost devices with a static configuration, which restricts the scanning of large surfaces. In this study, we propose the use of commercial devices, such as mobile devices and portable thermography, to integrate information from different wavelengths onto the surface of a 3D model. A handheld acquisition is proposed in which color images are used to create a 3D model by using Structure from Motion (SfM), and thermography is incorporated into the 3D surface through a pose estimation refinement based on optimizing the temperature correlation between multiple views. Thermal and color 3D models were successfully created for six patients with multiple views from a low-cost commercial device. The results show the successful application of the proposed methodology where thermal mapping on 3D models is not limited in the scanning area and can provide consistent information between multiple thermal camera views. Further work will focus on studying the quantitative metrics obtained by the multi-view 3D models created with the proposed methodology.

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Blaser, S., J. Meyer et S. Nebiker. « OPEN URBAN AND FOREST DATASETS FROM A HIGH-PERFORMANCE MOBILE MAPPING BACKPACK – A CONTRIBUTION FOR ADVANCING THE CREATION OF DIGITAL CITY TWINS ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2021 (28 juin 2021) : 125–31. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2021-125-2021.

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Abstract. With this contribution, we describe and publish two high-quality street-level datasets, captured with a portable high-performance Mobile Mapping System (MMS). The datasets will be freely available for scientific use. Both datasets, from a city centre and a forest represent area-wide street-level reality captures which can be used e.g. for establishing cloud-based frameworks for infrastructure management as well as for smart city and forestry applications. The quality of these data sets has been thoroughly evaluated and demonstrated. For example, georeferencing accuracies in the centimetre range using these datasets in combination with image-based georeferencing have been achieved. Both high-quality multi sensor system street-level datasets are suitable for evaluating and improving methods for multiple tasks related to high-precision 3D reality capture and the creation of digital twins. Potential applications range from localization and georeferencing, dense image matching and 3D reconstruction to combined methods such as simultaneous localization and mapping and structure-from-motion as well as classification and scene interpretation. Our dataset is available online at: https://www.fhnw.ch/habg/bimage-datasets

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Raffi, Francesca. « Full Access to Cultural Spaces (FACS) : Mapping and evaluating museum access services using mobile eye-tracking technology ». Ars Aeterna 9, n^o 2 (20 décembre 2017) : 18–38. http://dx.doi.org/10.1515/aa-2017-0007.

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Abstract The present paper aims to present significant results stemming from the FACS (Full Access to Cultural Spaces) project, launched in 2014 by the University of Macerata and concluded in 2016. In particular, this paper reports on stages one and two of the FACS project which aimed first to explore the state of the art of universal access services across a large variety of museums in Italy and nine other EU countries. Based on the first stage, an analysis of some of the most significant data obtained from a questionnaire sent out to over 1,200 European museums will be presented, with a special focus on multilingual devices and access services for the sensory impaired. The first stage was followed by an eye-tracking study on an Italian museum, Turin’s Museo Nazionale del Cinema (National Cinema Museum), aimed at evaluating visitors’ experience, attitudes and patterns of fruition through a test with a portable eye tracker (Tobii Pro Glasses 2, 50 Hz). Based on this second stage, the fruition of information panels by museum visitors at the Museo Nazionale del Cinema will be explored, specifically focusing on reading patterns and behaviours.

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Sammartano, G., A. Spanò et L. Teppati Losè. « A FUSION-BASED WORKFLOW FOR TURNING SLAM POINT CLOUDS AND FISHEYE DATA INTO TEXTURE-ENHANCED 3D MODELS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W17 (29 novembre 2019) : 295–302. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w17-295-2019.

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Abstract. Mobile mapping systems are increasingly developing ad hoc solution and integrated approaches for rapid and accurate 3D digitization in different operating environments belonging to built heritage assets. The use of emerging compact, portable and low-cost solution for imaging and ranging well fits in the purposes of mapping complex indoor spaces especially for narrow and underground ones (tunnels, mines, caves and ancient spaces), that are very challenging contexts in which to experiment integrated technological solutions and tailored workflows. In these cases, the main key issues are generally the difficulty in the seamless positioning and the complete and successful metric-radiometric content association in metric surface, due to the reduced manoeuvring space and complex lighting conditions. The prevalent goals for which the 3D digitization could be conceived are, beyond the accurate metric documentation, the analysis of mutual relations of volumes in complex structures, the virtual reconstruction and navigation of spaces with reduced accessibility for dissemination aims. The new SLAM-based positioning solutions implemented in some recent portable systems for indoor/outdoor mapping are increasingly developing and favoured by geometric features extraction algorithms even in traveling through complex and irregular environments. In parallel, the possibility to exploit the advances in digital photogrammetry algorithms for image matching and dense reconstruction using action-cam, compact and fisheye cameras allows to deploy investigation solutions even in complex environments at first sight impossible to map by photogrammetric approach. Here within the F.I.N.E. benchmark in the site of the San Vigilio Castle (Bergamo) and the “nottole” tunnels, a fusion-based workflow is proposed. It is focused on the purposes of providing radiometrically enriched 3D data from the possibility to colourized ZEB point cloud and a textured mesh surfaces with an oriented image block, taking care of the time processing steps optimization.

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Holdener, D., S. Nebiker et S. Blaser. « DESIGN AND IMPLEMENTATION OF A NOVEL PORTABLE 360° STEREO CAMERA SYSTEM WITH LOW-COST ACTION CAMERAS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W8 (13 novembre 2017) : 105–10. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w8-105-2017.

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The demand for capturing indoor spaces is rising with the digitalization trend in the construction industry. An efficient solution for measuring challenging indoor environments is mobile mapping. Image-based systems with 360° panoramic coverage allow a rapid data acquisition and can be processed to georeferenced 3D images hosted in cloud-based 3D geoinformation services. For the multiview stereo camera system presented in this paper, a 360° coverage is achieved with a layout consisting of five horizontal stereo image pairs in a circular arrangement. The design is implemented as a low-cost solution based on a 3D printed camera rig and action cameras with fisheye lenses. The fisheye stereo system is successfully calibrated with accuracies sufficient for the applied measurement task. A comparison of 3D distances with reference data delivers maximal deviations of 3 cm on typical distances in indoor space of 2-8 m. Also the automatic computation of coloured point clouds from the stereo pairs is demonstrated.

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Yasutake, Akira, Jin Ping Cheng, Masako Kiyono, Shimpei Uraguchi, Xiaojie Liu, Kyoko Miura, Yoshiaki Yasuda et Nikolay Mashyanov. « Rapid Monitoring of Mercury in Air from an Organic Chemical Factory in China Using a Portable Mercury Analyzer ». Scientific World JOURNAL 11 (2011) : 1630–40. http://dx.doi.org/10.1100/2011/493207.

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A chemical factory, using a production technology of acetaldehyde with mercury catalysis, was located southeast of Qingzhen City in Guizhou Province, China. Previous research showed heavy mercury pollution through an extensive downstream area. A current investigation of the mercury distribution in ambient air, soils, and plants suggests that mobile mercury species in soils created elevated mercury concentrations in ambient air and vegetation. Mercury concentrations of up to 600 ng/m3in air over the contaminated area provided evidence of the mercury transformation to volatile Hg(0). Mercury analysis of soil and plant samples demonstrated that the mercury concentrations in soil with vaporized and plant-absorbable forms were higher in the southern area, which was closer to the factory. Our results suggest that air monitoring using a portable mercury analyzer can be a convenient and useful method for the rapid detection and mapping of mercury pollution in advanced field surveys.

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Abburu, Sunitha. « GIS Based Health Information Management through LETL, Multi Criteria Query, Analysis, Visualization ». International Journal of E-Health and Medical Communications 10, n^o 1 (janvier 2019) : 38–54. http://dx.doi.org/10.4018/ijehmc.2019010103.

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For effective decision making in public health information management(HIM) system, health information availability, accessibility, prompt exchange, GIS linkage, spatiotemporal analysis of diseases is crucial. Lack of cost-effective technical support and information gaps are the main obstacles in HIM. This article defines a generic conceptual process framework for effective HIM that provides cost-effective, portable, easy to use solution. The solution incorporates GIS, Mobile technology, information management concepts, ICD-10 codes, WHO and mHealth standards. The current research is implemented as an android application that facilitates: 1) Patient disease data collection, geospatial mapping of disease data and accumulate a centralized server 2) LETL that supports bulk disease data upload 3) Addresses syntactic and semantic heterogeneity in health data 4) A strong multi-criteria query engine, visualization and spatiotemporal analysis of diseases are designed with a global perspective to be used across the globe.

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Dhonju, Hari, Wen Xiao, Jon Mills et Vasilis Sarhosis. « Share Our Cultural Heritage (SOCH) : Worldwide 3D Heritage Reconstruction and Visualization via Web and Mobile GIS ». ISPRS International Journal of Geo-Information 7, n^o 9 (30 août 2018) : 360. http://dx.doi.org/10.3390/ijgi7090360.

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Despite being of paramount importance to humanity, tangible cultural heritage is often at risk from natural and anthropogenic threats worldwide. As a result, heritage discovery and conservation remain a huge challenge for both developed and developing countries, with heritage sites often inadequately cared for, be it due to a lack of resources, nonrecognition of the value by local people or authorities, human conflict, or some other reason. This paper presents an online geo-crowdsourcing system, termed Share Our Cultural Heritage (SOCH), which can be utilized for large-scale heritage documentation and sharing. Supported by web and mobile GIS, cultural heritage data such as textual stories, locations, and images can be acquired via portable devices. These data are georeferenced and presented to the public via web-mapping. Using photogrammetric modelling, acquired images are used to reconstruct heritage structures or artefacts into 3D digital models, which are then visualized on the SOCH web interface to enable public interaction. This end-to-end system incubates an online virtual community to encourage public engagement, raise awareness, and stimulate cultural heritage ownership. It also provides valuable resources for cultural heritage exploitation, management, education, and monitoring over time.

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Hart, Ronan, Lu Liang et Pinliang Dong. « Monitoring, Mapping, and Modeling Spatial–Temporal Patterns of PM2.5 for Improved Understanding of Air Pollution Dynamics Using Portable Sensing Technologies ». International Journal of Environmental Research and Public Health 17, n^o 14 (8 juillet 2020) : 4914. http://dx.doi.org/10.3390/ijerph17144914.

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Fine particulate matter with an aerodynamic diameter of less than 2.5 µm (PM2.5) is highly variable in space and time. In this study, the dynamics of PM2.5 concentrations were mapped at high spatio-temporal resolutions using bicycle-based, mobile measures on a university campus. Significant diurnal and daily variations were revealed over the two-week survey, with the PM2.5 concentration peaking during the evening rush hours. A range of predictor variables that have been proven useful in estimating the pollution level was derived from Geographic Information System, high-resolution airborne images, and Light Detection and Ranging (LiDAR) datasets. Considering the complex interplay among landscape, wind, and air pollution, variables influencing the PM2.5 dynamics were quantified under a new wind wedge-based system that incorporates wind effects. Panel data analysis models identified eight natural and built environment variables as the most significant determinants of local-scale air quality (including four meteorological factors, distance to major roads, vegetation footprint, and building and vegetation height). The higher significance level of variables calculated using the wind wedge system as compared to the conventional circular buffer highlights the importance of incorporating the relative position of emission sources and receptors in modeling.

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Menna, F., A. Torresani, R. Battisti, E. Nocerino et F. Remondino. « A MODULAR AND LOW-COST PORTABLE VSLAM SYSTEM FOR REAL-TIME 3D MAPPING : FROM INDOOR AND OUTDOOR SPACES TO UNDERWATER ENVIRONMENTS ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-2/W1-2022 (8 décembre 2022) : 153–62. http://dx.doi.org/10.5194/isprs-archives-xlviii-2-w1-2022-153-2022.

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Abstract. The bond with computer vision and robotics is revolutionizing the traditional surveying approaches. Algorithms such as visual odometry and SLAM are embedded in surveying systems to make on-site and processing operations more efficient both in terms of time and quality of the achieved results. In this paper, we present the latest developments on GuPho, a mobile mapping concept based on photogrammetry that leverages a vSLAM solution to provide innovative and unique features supporting the image acquisition and optimising the processing steps. These include visual feedback on ground sample distance and maximum allowed speed to avoid motion blur. Two efficient image acquisition strategies, based on geometric principles, are implemented to optimise the disk storage, avoiding unnecessary redundancy. Moreover, an innovative automatic exposure control that adjusts the shutter speed or gain based on the tracked object in 3D is part of the system. The paper reports the motivations behind the design choices, details the hardware and software components, discusses several case studies to showcase the potentialities of our low-cost, lightweight, and portable modular prototype system.

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Chen, C., B. S. Yang et S. Song. « LOW COST AND EFFICIENT 3D INDOOR MAPPING USING MULTIPLE CONSUMER RGB-D CAMERAS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (2 juin 2016) : 169–74. http://dx.doi.org/10.5194/isprsarchives-xli-b1-169-2016.

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Driven by the miniaturization, lightweight of positioning and remote sensing sensors as well as the urgent needs for fusing indoor and outdoor maps for next generation navigation, 3D indoor mapping from mobile scanning is a hot research and application topic. The point clouds with auxiliary data such as colour, infrared images derived from 3D indoor mobile mapping suite can be used in a variety of novel applications, including indoor scene visualization, automated floorplan generation, gaming, reverse engineering, navigation, simulation and etc. State-of-the-art 3D indoor mapping systems equipped with multiple laser scanners product accurate point clouds of building interiors containing billions of points. However, these laser scanner based systems are mostly expensive and not portable. Low cost consumer RGB-D Cameras provides an alternative way to solve the core challenge of indoor mapping that is capturing detailed underlying geometry of the building interiors. Nevertheless, RGB-D Cameras have a very limited field of view resulting in low efficiency in the data collecting stage and incomplete dataset that missing major building structures (e.g. ceilings, walls). Endeavour to collect a complete scene without data blanks using single RGB-D Camera is not technic sound because of the large amount of human labour and position parameters need to be solved. To find an efficient and low cost way to solve the 3D indoor mapping, in this paper, we present an indoor mapping suite prototype that is built upon a novel calibration method which calibrates internal parameters and external parameters of multiple RGB-D Cameras. Three Kinect sensors are mounted on a rig with different view direction to form a large field of view. The calibration procedure is three folds: 1, the internal parameters of the colour and infrared camera inside each Kinect are calibrated using a chess board pattern, respectively; 2, the external parameters between the colour and infrared camera inside each Kinect are calibrated using a chess board pattern; 3, the external parameters between every Kinect are firstly calculated using a pre-set calibration field and further refined by an iterative closet point algorithm. Experiments are carried out to validate the proposed method upon RGB-D datasets collected by the indoor mapping suite prototype. The effectiveness and accuracy of the proposed method is evaluated by comparing the point clouds derived from the prototype with ground truth data collected by commercial terrestrial laser scanner at ultra-high density. The overall analysis of the results shows that the proposed method achieves seamless integration of multiple point clouds form different RGB-D cameras collected at 30 frame per second.

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Chen, C., B. S. Yang et S. Song. « LOW COST AND EFFICIENT 3D INDOOR MAPPING USING MULTIPLE CONSUMER RGB-D CAMERAS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (2 juin 2016) : 169–74. http://dx.doi.org/10.5194/isprs-archives-xli-b1-169-2016.

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Driven by the miniaturization, lightweight of positioning and remote sensing sensors as well as the urgent needs for fusing indoor and outdoor maps for next generation navigation, 3D indoor mapping from mobile scanning is a hot research and application topic. The point clouds with auxiliary data such as colour, infrared images derived from 3D indoor mobile mapping suite can be used in a variety of novel applications, including indoor scene visualization, automated floorplan generation, gaming, reverse engineering, navigation, simulation and etc. State-of-the-art 3D indoor mapping systems equipped with multiple laser scanners product accurate point clouds of building interiors containing billions of points. However, these laser scanner based systems are mostly expensive and not portable. Low cost consumer RGB-D Cameras provides an alternative way to solve the core challenge of indoor mapping that is capturing detailed underlying geometry of the building interiors. Nevertheless, RGB-D Cameras have a very limited field of view resulting in low efficiency in the data collecting stage and incomplete dataset that missing major building structures (e.g. ceilings, walls). Endeavour to collect a complete scene without data blanks using single RGB-D Camera is not technic sound because of the large amount of human labour and position parameters need to be solved. To find an efficient and low cost way to solve the 3D indoor mapping, in this paper, we present an indoor mapping suite prototype that is built upon a novel calibration method which calibrates internal parameters and external parameters of multiple RGB-D Cameras. Three Kinect sensors are mounted on a rig with different view direction to form a large field of view. The calibration procedure is three folds: 1, the internal parameters of the colour and infrared camera inside each Kinect are calibrated using a chess board pattern, respectively; 2, the external parameters between the colour and infrared camera inside each Kinect are calibrated using a chess board pattern; 3, the external parameters between every Kinect are firstly calculated using a pre-set calibration field and further refined by an iterative closet point algorithm. Experiments are carried out to validate the proposed method upon RGB-D datasets collected by the indoor mapping suite prototype. The effectiveness and accuracy of the proposed method is evaluated by comparing the point clouds derived from the prototype with ground truth data collected by commercial terrestrial laser scanner at ultra-high density. The overall analysis of the results shows that the proposed method achieves seamless integration of multiple point clouds form different RGB-D cameras collected at 30 frame per second.

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Bonfanti, C., G. Patrucco, S. Perri, G. Sammartano et A. Spanò. « A NEW INDOOR LIDAR-BASED MMS CHALLENGING COMPLEX ARCHITECTURAL ENVIRONMENTS ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-M-1-2021 (28 août 2021) : 79–86. http://dx.doi.org/10.5194/isprs-archives-xlvi-m-1-2021-79-2021.

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Abstract. The use of moving devices equipped with range- and image-based sensor, generically defined Mobile Mapping systems (MMS), have been quite a disruptive innovation in the development of Geomatics techniques for 3D surveying large indoor-outdoor spaces and offer multiple solutions. The recent expansion of portable devices in the form of trolleys, backpacks, handheld tools largely implements SLAM (Simultaneous Localization and Mapping) algorithms and technology based on both Lidar and/or visual solutions for answering to the positioning and the 3D reconstruction problems. The research on MMS is directed to improve both multi-sensor integration implementation and usability of systems in diversified use contexts and application fields. The aim of the presented research is the evaluation of the potential of the Swift system recently developed by FARO Technologies, that has been fine-tuned for regular and large extent interiors mapping (such as factories, hospitals, airports, offices). The work tries to preliminary investigate the data delivery and usability of the integrated system. This is based on three elements mounted on a sliding trolley moved by the operator walking: the ScanPlan profilometer working for the 2D SLAM mapping, the static TLS Focus S-series, and the smartphone managing the sensors operation and the acquisition progress. The evaluation strategy undertaken will be based on the global and local performance analysis related to the trajectory, the data accuracy, the metric content and consistency. Two test studies belonging to the 20th century. architecture are presented in a preliminary framework of evaluation and validation: a Liberty-style cinema and the Torino Esposizioni Hall B designed in ferrocement by pier Luigi Nervi.

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Madleňák, Adam. « Geolocation Services and Marketing Communication from a Global Point of View ». SHS Web of Conferences 92 (2021) : 02040. http://dx.doi.org/10.1051/shsconf/20219202040.

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Research background: Electronic communication fundamentally influences social behavior of the society. An unlimited virtual connection to the outside world and the minimal costs needed to reach out to a particular subject cause personal contact to become of marginal importance. The starting point may be, in certain cases, the ability of a mobile device to provide interested parties with relatively accurate geographical data mapping the distribution of objects in space. Therefore, localization of individual participants in the communication process becomes a prerequisite for establishing a contact in the real world. Moreover, localization also serves as a tool for creating highly personalized messages based on a combination of geographical, demographic, psychographic and behavioral characteristics. Purpose of the article: The aim of the paper is to research the peculiarities associated with the localization of portable electronic devices in the space and the associated efforts to improve the level of personalized communication in line with the right timing of wireless distribution of advertising content to the recipient. Methods: In order to achieve the stated goal, the author made use of several research methods to research the use of localization technologies in software products supporting social interaction between users of portable electronic devices. In particular, the author used analytical, inductive, deductive and comparative research methods. The paper also contains the results of several scientific studies presenting the latest market trends reflecting on research from abroad. Findings & Value added: The paper contributes to the definition of the specifics that characterize the various types of localization technologies which convey information to the target audience within SoLoMo marketing.

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Boreiko, Maksym, et Mykola Budnyk. « Development of the Remote Heart Health Monitoring System ». Cybernetics and Computer Technologies, n^o 2 (30 juin 2021) : 90–98. http://dx.doi.org/10.34229/2707-451x.21.2.10.

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Introduction. Cardiovascular disease (CVD) is the most common cause of death worldwide. This problem is especially relevant for Ukraine, where CVD accounts for more than 68% of all deaths. At the same time, in terms of population mortality rate (15.3 ‰), Ukraine is ahead of all European countries. Electrocardiography is the most useful diagnostic tools. Nowadays a lot of portable ECG devices are available on the market, which makes ECG accessible for each patient directly from home. Remote monitoring of patients with CVD is a very necessary solution, which can save patient’s lives, doctor’s time and hospital’s money. Existing remote monitoring solution doesn’t provide enough cyber security and scalability, especially in the context of tight regulation of medical software in the European Union. The purpose of the article is to develop a cloud-based software solution for remote monitoring of patients with CVD using a portable ECG device. We propose the full architecture, which include server-side components (databases, computational resources, gateways, queus, load balancers and others) and client-side components (mobile app for the Android and iOS and web browser app). Results. We proposed, designed, implemented and tested the full end-to-end Cloud-based solution for remote monitoring of patients with CVD. Security of the system is ensured by dividing the single database to three separate databases (database with patient’s data, database with ECG data and mapping database), hiding all server components under the virtual private network, and transferring data via secure HTTPS connection. Conclusions. Developed system successfully solve their goals. It is being used now in the Finnish company Cardiolyse. Keywords: telemedicine, client-server, medical devices, electrocardiography, cybersecurity, heart rate variability

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Peel, M. W., C. A. Wuensche, E. Abdalla, S. Antón, L. Barosi, I. W. A. Browne, M. Caldas et al. « Baryon Acoustic Oscillations from Integrated Neutral Gas Observations : Radio Frequency Interference Measurements and Telescope Site Selection ». Journal of Astronomical Instrumentation 08, n^o 01 (mars 2019) : 1940005. http://dx.doi.org/10.1142/s2251171719400051.

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The Baryon acoustic oscillations from Integrated Neutral Gas Observations (BINGO) telescope is a new 40[Formula: see text]m class radio telescope to measure the large-angular-scale intensity of H i emission at 980–1260[Formula: see text]MHz to constrain dark energy parameters. As it needs to measure faint cosmological signals at the milliKelvin level, it requires a site that has very low radio frequency interference (RFI) at frequencies around 1[Formula: see text]GHz. We report on measurement campaigns across Uruguay and Brazil to find a suitable site, which looked at the strength of the mobile phone signals and other radio transmissions, the location of wind turbines, and also included mapping airplane flight paths. The site chosen for the BINGO telescope is a valley at Serra do Urubu, a remote part of Paraíba in North-East Brazil, which has sheltering terrain. During our measurements with a portable receiver, we did not detect any RFI in or near the BINGO band, given the sensitivity of the equipment. A radio quiet zone around the selected site has been requested from the Brazilian authorities ahead of the telescope construction.

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Bronzino, G. P. C., N. Grasso, F. Matrone, A. Osello et M. Piras. « LASER-VISUAL-INERTIAL ODOMETRY BASED SOLUTION FOR 3D HERITAGE MODELING : THE SANCTUARY OF THE BLESSED VIRGIN OF TROMPONE ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W15 (20 août 2019) : 215–22. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w15-215-2019.

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Abstract. The advent of new mobile mapping systems that integrate different sensors has made it easier to acquire multiple 3D information with high speed. Today, technological development has allowed the creation of portable systems particularly suitable for indoor surveys, which mainly integrating LiDAR devices, chambers and inertial platforms, make it possible to create in a fast and easy way, full 3D model of the environment. However, the performance of these instruments differs depending on the acquisition context (indoor and outdoor), the characteristics of the scene (for example lighting, the presence of objects and people, reflecting surfaces, textures) and, above all, the mapping and localization algorithms implemented in devices. The purpose of this study is to analyse the results, and their accuracy, deriving from a survey conducted with the KAARTA Stencil 2 handheld system. This instrument, composed of a 3D LiDAR Velodyne VLP-16, a MEMS inertial platform and a feature tracker camera, it is able to realize the temporal 3D map of the environment. Specifically, the acquisition tests were carried out in a context of metrical documentation of an architectural heritage, in order extract architectural detail for the future reconstruction of virtual and augmented reality environments and for Historical Building Information Modeling purposes. The achieved results were analysed and the discrepancies from some reference LiDAR data are computed for a final evaluation. The system was tested in the church and cloister of the Sanctuary of the Beata Vergine del Trompone in Moncrivello (VC) (Italy).

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Wierzbicki, D., et P. Stogowski. « APPLICATION OF STEREO CAMERAS WITH WIDE-ANGLE LENSES FOR THE INDOOR MAPPING ». International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2022 (30 mai 2022) : 477–84. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2022-477-2022.

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Abstract. Recently, there has been an increase in interest in the use of wide-angle cameras in multi-image matching for the indoor 3D mapping and indoor localization. The demand for rapid 3D models of spaces in unknown environments is increasingly observed. That is particularly important when modelling unknown objects to conduct reconnaissance or building intervention after a disaster. In this case, developing a 3D model using a robot equipped with a system of synchronized stereo cameras with a short length longitudinal base is extremely desirable. In these studies, we present the approach to indoor location based on a 3D model developed from a dense point cloud with multi-image matching technique. As part of the research, an imaging system was developed, and an algorithm that converts images of selected objects to 3D model was implemented. The research presents the method of determining the object position based on the calculation of reference points’ disparity based on the Sum of Absolute Differences (SAD). Next, a dense point cloud was generated based on the method of mutual image matching using Structure from Motion (SfM) algorithms. The resulting dense cloud of points had a resolution of 0.05 m. Based on the developed algorithm, a method for generating a quick model of the environment based on multi-image matching and disparity maps was presented. The obtained test results confirmed the possibilities of using the developed methodology for the needs of rapid reconnaissance of the environment to determine the distance, location and size of objects of interest. The mapping accuracy is at a decimeter level, and the possibility of geolocation of objects can be performed with an accuracy of ± 0.15 m. Based on the obtained test results, the potential of using miniature, portable mobile image-based mapping systems has been demonstrated to identify and model inaccessible rooms. Further work will be focused on the improvement of the geometric image quality and to increase the accuracy of the calibration.

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Wahbeh, W., M. Ammann, S. Nebiker, M. van Eggermond et A. Erath. « IMAGE-BASED REALITY-CAPTURING AND 3D MODELLING FOR THE CREATION OF VR CYCLING SIMULATIONS ». ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences V-4-2021 (17 juin 2021) : 225–32. http://dx.doi.org/10.5194/isprs-annals-v-4-2021-225-2021.

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Abstract. With this paper, we present a novel approach for efficiently creating reality-based, high-fidelity urban 3D models for interactive VR cycling simulations. The foundation of these 3D models is accurately georeferenced street-level imagery, which can be captured using vehicle-based or portable mapping platforms. Depending on the desired type of urban model, the street-level imagery is either used for semi-automatically texturing an existing city model or for automatically creating textured 3D meshes from multi-view reconstructions using commercial off-the-shelf software. The resulting textured urban 3D model is then integrated with a real-time traffic simulation solution to create a VR framework based on the Unity game engine. Subsequently, the resulting urban scenes and different planning scenarios can be explored on a physical cycling simulator using a VR helmet or viewed as a 360-degree or conventional video. In addition, the VR environment can be used for augmented reality applications, e.g., mobile augmented reality maps. We apply this framework to a case study in the city of Berne to illustrate design variants of new cycling infrastructure at a major traffic junction to collect feedback from practitioners about the potential for practical applications in planning processes.

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Ma, Rui, Jia Wang, Wei Zhao, Hongjie Guo, Dongnan Dai, Yuliang Yun, Li Li, Fengqi Hao, Jinqiang Bai et Dexin Ma. « Identification of Maize Seed Varieties Using MobileNetV2 with Improved Attention Mechanism CBAM ». Agriculture 13, n^o 1 (21 décembre 2022) : 11. http://dx.doi.org/10.3390/agriculture13010011.

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Seeds are the most fundamental and significant production tool in agriculture. They play a critical role in boosting the output and revenue of agriculture. To achieve rapid identification and protection of maize seeds, 3938 images of 11 different types of maize seeds were collected for the experiment, along with a combination of germ and non-germ surface datasets. The training set, validation set, and test set were randomly divided by a ratio of 7:2:1. The experiment introduced the CBAM (Convolutional Block Attention Module) attention mechanism into MobileNetV2, improving the CBAM by replacing the cascade connection with a parallel connection, thus building an advanced mixed attention module, I_CBAM, and establishing a new model, I_CBAM_MobileNetV2. The proposed I_CBAM_MobileNetV2 achieved an accuracy of 98.21%, which was 4.88% higher than that of MobileNetV2. Compared to Xception, MobileNetV3, DenseNet121, E-AlexNet, and ResNet50, the accuracy was increased by 9.24%, 6.42%, 3.85%, 3.59%, and 2.57%, respectively. Gradient-Weighted Class Activation Mapping (Grad-CAM) network visualization demonstrates that I_CBAM_MobileNetV2 focuses more on distinguishing features in maize seed images, thereby boosting the accuracy of the model. Furthermore, the model is only 25.1 MB, making it suitable for portable deployment on mobile terminals. This study provides effective strategies and experimental methods for identifying maize seed varieties using deep learning technology. This research provides technical assistance for the non-destructive detection and automatic identification of maize seed varieties.

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Salamone, Francesco, Sergio Sibilio et Massimiliano Masullo. « Assessment of the Performance of a Portable, Low-Cost and Open-Source Device for Luminance Mapping through a DIY Approach for Massive Application from a Human-Centred Perspective ». Sensors 22, n^o 20 (11 octobre 2022) : 7706. http://dx.doi.org/10.3390/s22207706.

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Ubiquitous computing has enabled the proliferation of low-cost solutions for capturing information about the user’s environment or biometric parameters. In this sense, the do-it-yourself (DIY) approach to build new low-cost systems or verify the correspondence of low-cost systems compared to professional devices allows the spread of application possibilities. Following this trend, the authors aim to present a complete DIY and replicable procedure to evaluate the performance of a low-cost video luminance meter consisting of a Raspberry Pi and a camera module. The method initially consists of designing and developing a LED panel and a light cube that serves as reference illuminance sources. The luminance distribution along the two reference light sources is determined using a Konica Minolta luminance meter. With this approach, it is possible to identify an area for each light source with an almost equal luminance value. By applying a frame that covers part of the panel and shows only the area with nearly homogeneous luminance values and applying the two systems in a dark space in front of the low-cost video luminance meter mounted on a professional reference camera photometer LMK mobile air, it is possible to check the discrepancy in luminance values between the low-cost and professional systems when pointing different homogeneous light sources. In doing so, we primarily consider the peripheral shading effect, better known as the vignetting effect. We then differentiate the correction factor S of the Radiance Pcomb function to better match the luminance values of the low-cost system to the professional device. We also introduce an algorithm to differentiate the S factor depending on the light source. In general, the DIY calibration process described in the paper is time-consuming. However, the subsequent applications in various real-life scenarios allow us to verify the satisfactory performance of the low-cost system in terms of luminance mapping and glare evaluation compared to a professional device.

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Brovelli, Maria Antonia, Candan Eylül Kilsedar et Francesco Frassinelli. « Mobile Tools for Community Scientists ». Abstracts of the ICA 1 (15 juillet 2019) : 1–3. http://dx.doi.org/10.5194/ica-abs-1-30-2019.

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Abstract. While public participation in scientific achievements has a long history, the last decades have seen more attention and an impressive increase in the number of involved people. Citizen science, the term used for denoting such an attitude, is a very diverse practice, encompassing various forms, depths, and aims of collaboration between scientists and citizen researchers and a broad range of scientific disciplines. Different classifications of citizen science projects exist based on the degrees of influence and contributions of citizens. Haklay, Mazumdar, and Wardlaw (2018) distinguish the citizen science projects in three different classes: <ol><li>Long-running citizen science, which are the traditional ones, the projects similar to those run in the past (Koboriet al., 2016; Bonney et al., 2009)</li> <li>Citizen cyberscience, strictly connected with the use of technologies (Grey, 2009) and which can be subclassified in:<ol><li>volunteer computing, where citizens offer the unused computing resources of their computers;</li><li>volunteer thinking, where citizens offer their cognitive abilities for performing tasks difficult for machines;</li><li>passive sensing, where citizens use the sensors integrated into mobile computing devices to carry outautomatic sensing tasks.</li></ol></li> <li>Community science, involving a more significant commitment of citizens also in designing and planning theproject activities in a more egalitarian (if not bottom-up) approach between scientists and citizen scientists(Jepson & Ladle, 2015; Nascimento, Guimarães Pereira, & Ghezzi, 2014; Breen, Dosemagen, Warren, &Lippincott, 2015), which can be divided into:<ol><li>participatory sensing, where citizens use the sensors integrated into mobile computing devices to carry outsensing tasks;</li><li>Do It Yourself (DIY) science, which implies participants create their scientific tools and methodology to carry out their researches; </li><li>civic science, “which is explicitly linked to community goals and questions the state of things” (Haklay et al., 2018).</li></ol></li></ol> The work presented here is of interest of community scientists which voluntarily offer their time for the development of scientific projects. Many software tools have been developed in order to simplify the insertion of data into structured forms and the aggregation and analysis of the obtained data. In recent years, the growing availability of feature-rich and low-cost smartphones have boosted the development of innovative solutions for data collection using portable devices. In this field, ODK (OpenDataKit) is widely known. It is an open-source suite of tools focused on simplicity of use, which includes an Android application for data collection. We used ODK for the first applications we developed.One of the applications we developed using ODK is Via Regina (http://www.viaregina.eu/app). The application aims to support slow tourism in Via Regina, which is a road that overlooks the west coast of Lake Como in Northern Italy. Over the centuries, Via Regina has been a critical trade and pilgrim route in Europe. Moreover, from this road, a compact system of slow mobility paths departs, which span the mountainous region at the border between Italy and Switzerland. This region is rich in culture, regarding history, art, architecture, cuisine and people’s lifestyle. Considering collecting data on Via Regina and the paths around it would enable to rediscover and promote its culture while enjoying the territory, an Interreg project named “The Paths of Regina” started. The application developed within this project allows collecting data in predefined types: historical and cultural, morphological, touristic, and critical. Moreover, while reporting a point of interest (POI), the application asks the name, the position (through GPS or an interactive map), a picture, and optionally a video and an audio record of it (Antonovic et al., 2015).However, since ODK application can be used only on Android devices, we developed a cross-platform application to collect similar data for the same purpose. It is available on Android, iOS, and web (http://viaregina3.como.polimi.it/app/). The application is developed using Apache Cordova, which is a mobile application development framework that enables running the application in multiple platforms. Leaflet library is used for web mapping. The data is stored in NoSQL PouchDB and CouchDB database, which enables both online and offline data collection. While reporting a POI, the application asks for its type, the user’s rating, a comment, and a picture of it either uploaded from device’s storage or taken using the camera of the mobile device. In addition to being cross-platform, it has the advantage of displaying and enabling the query of POIs reported, compared to the ODK-based version (Brovelli, Kilsedar, & Zamboni, 2016). Regarding citizen science, besides the citizens using these two applications, Iubilantes, a voluntary cultural organization, has been involved in the project as community scientists. Iubilantes created slow mobility paths to walk in and around Via Regina, using their experience gained through studying ancient paths while protecting and enhancing their assets since 1996.Mobile data collection can also be used to compensate for the lack of reference data available for land cover validation. We developed the Land Cover Collector (https://github.com/kilsedar/land-cover-collector) application for this purpose, which collects data using the nomenclature of GlobeLand30. GlobeLand30 is the first global land cover map at 30-meter resolution, provided by National Geomatics Center of China, available for 2000 and 2010 (Chen et al., 2015). There are ten land cover classes in the GlobeLand30 dataset, which are: artificial surface, bare land, cultivated land, forest, grassland, permanent snow and ice, shrubland, tundra, water body, and wetland. The collected data will be used for validating GlobeLand30 (Kilsedar, Bratic, Molinari, Minghini, & Brovelli, 2018). The data is licensed under the Open Database License (ODbL) v1.0 and can be downloaded within the application in JSON format. The application is currently available in eight languages: English, Italian, Arabic, Russian, Chinese, Portuguese, French and Spanish. The technologies used are the same as the cross-platform Via Regina application. As a result, it is available on Android, iOS, and web (https://landcover.como.polimi.it/collector/); and it supports display and query of the collected data. While reporting a POI, the application asks the land cover class of it, the user’s degree of certainty on the correctness of the stated class, photos in north, east, south and west directions, and the user’s comment. Three hands-on workshops were given to teach this application and various ways to validate GlobeLand30: the first on September 1, 2018 at the World Bank in Dar es Salaam, Tanzania (in conjunction with the FOSS4G 2018 conference); the second on September 3, 2018 at the Regional Centre for Mapping of Resources for Development (RCMRD) in Nairobi, Kenya; and the third on October 1, 2018 at the Delft University of Technology in Delft, Netherlands. The workshops, run by representatives of the project's principal investigators &ndash; Politecnico di Milano (Italy) and the National Geomatics Center of China (China) &ndash; were attended by a total of 100 people with a background in GIS and remote sensing. (Brovelli et al., 2018).Nonetheless, there are no widely adopted cross-platform open-source solutions or systems for on-site surveys that address the problem of information silos: isolated databases, where the information is not adequately shared but rather remains sequestered within each system, which is an obstacle to using data mining to make productive use of data of multiple systems. PSAB (Participatory Sensing App Builder) is a platform that provides an open-source and easy to use cross-platform solution for the creation of custom smartphone applications as well as web applications and catalog service for publishing the data and make them available to everyone. It takes advantage of established standards (like XLSForm for defining the structure of the form and DublinCore for exposing metadata) as well as less known yet effective solutions, like WQ (https://wq.io), a framework developed for building reusable software platforms for citizen science. These technologies have been merged, together with other software like Django, PyCSW, PostgreSQL, in a single solution, in order to assist the user during the entire process, from the definition of the form structure, to the creation of an ad-hoc application and the publication of the collected data, inside a flexible and open-source platform. Users registered to PSAB are allowed to create a new application by filling a web form where they can upload their XLSForm files and submit the metadata describing the data to be collected. A new application for collecting data on the field is generated and accessible via web and Android (while iOS requires a particular setup), ready to be used online and offline. The creator of each application is also the administrator of it, which means he/she is allowed to add or ban users and modify or remove existing data. Data is automatically synchronized between all the users participating in the project. In the presentation we will show the applications we developed, starting from the ODK-based ones and coming to the PSAB application builder, and our experience related to their usage.

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Heinz, Erik, Christian Eling, Markus Wieland, Lasse Klingbeil et Heiner Kuhlmann. « Development, Calibration and Evaluation of a Portable and Direct Georeferenced Laser Scanning System for Kinematic 3D Mapping ». Journal of Applied Geodesy 9, n^o 4 (1 janvier 2015). http://dx.doi.org/10.1515/jag-2015-0011.

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AbstractIn recent years, kinematic laser scanning has become increasingly popular because it offers many benefits compared to static laser scanning. The advantages include both saving of time in the georeferencing and a more favorable scanning geometry. Often mobile laser scanning systems are installed on wheeled platforms, which may not reach all parts of the object. Hence, there is an interest in the development of portable systems, which remain operational even in inaccessible areas. The development of such a portable laser scanning system is presented in this paper. It consists of a lightweight direct georeferencing unit for the position and attitude determination and a small low-cost 2D laser scanner. This setup provides advantages over existing portable systems that employ heavy and expensive 3D laser scanners in a profiling mode.A special emphasis is placed on the system calibration, i. e. the determination of the transformation between the coordinate frames of the direct georeferencing unit and the 2D laser scanner. To this end, a calibration field is used, which consists of differently orientated georeferenced planar surfaces, leading to estimates for the lever arms and boresight angles with an accuracy of mm and one-tenth of a degree. Finally, point clouds of the mobile laser scanning system are compared with georeferenced point clouds of a high-precision 3D laser scanner. Accordingly, the accuracy of the system is in the order of cm to dm. This is in good agreement with the expected accuracy, which has been derived from the error propagation of previously estimated variance components.

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